1. Field
An aspect of the present disclosure relates to an optical signal processing apparatus using a planar lightwave circuit with a waveguide-array structure.
2. Description of the Related Art
An optical channel monitor (OCM) monitors the intensity, wavelength, etc. of a wavelength division multiplexing (WDM) optical signal (hereinafter, referred to as a WDM optical signal) input or output from a node of a metro or long-distance network. The OCM monitoring the WDM optical signal is commercialized based on various techniques in many companies (JDSU, Finisar, Axsun, DiCon, LambdaQuest, Photop, Optoplex, etc.).
A technique using an optical resonance structure-based wavelength-tunable optical filter and a technique using diffraction grating are representative of techniques for implementing the OCM. When the wavelength-tunable optical filter is used, a technique for accurately controlling the length of an optical resonance structure using MEMS is required. When the diffraction grating is used, the OCM is configured with bulk-type optical components. Hence, a technique for accurately aligning and assembling optical components is required, and the size of the OCM increases.
As described above, the typical technique for implementing the OCM is restrictively applied to a metro or long-distance optical communication system in terms of price and size. In addition, a minority of companies has monopolized the technique due to its very high accuracy and complexity.